First, please check the following regarding your sensor.
・ Is it Bluetooth compatible?
・ Does the battery have sufficient charge?
・ Is it turned ON?
・ Is it in the waiting for connection status (advertising)?
・ Is it securely fastened to the bicycle?
* In addition, please refer to manuals for instructions on how to use the sensor.
Also, when you connect to the sensor for the first time, it has to be paired with E-TUBE RIDE.
Put the sensor into the advertising status, then tap the "Add" button on the connection screen to pair with E-TUBE RIDE.
If the sensor is disconnected after pairing, check to see if the sensor is connected to a smartphone or other devices. Disconnect other devices if any are connected.
* For information on connectible sensors, see "What type of sensors can be connected? (R-5200)".